linux-kernel - [PATCH v1 2/6] powerpc/8xx: Always pin kernel text TLB

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Message-Id: <203b89de491e1379f1677a2685211b7c32adfff0.1606231483.git.christophe.leroy@csgroup.eu>
Date:   Tue, 24 Nov 2020 15:24:55 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 2/6] powerpc/8xx: Always pin kernel text TLB

There is no big poing in not pinning kernel text anymore, as now
we can keep pinned TLB even with things like DEBUG_PAGEALLOC.

Remove CONFIG_PIN_TLB_TEXT, making it always right.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/Kconfig               |  3 +--
 arch/powerpc/kernel/head_8xx.S     | 20 +++-----------------
 arch/powerpc/mm/nohash/8xx.c       |  3 +--
 arch/powerpc/platforms/8xx/Kconfig |  7 -------
 4 files changed, 5 insertions(+), 28 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e9f13fe08492..bf088b5b0a89 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -795,8 +795,7 @@ config DATA_SHIFT_BOOL
 	bool "Set custom data alignment"
 	depends on ADVANCED_OPTIONS
 	depends on STRICT_KERNEL_RWX || DEBUG_PAGEALLOC
-	depends on PPC_BOOK3S_32 || (PPC_8xx && !PIN_TLB_DATA && \
-				     (!PIN_TLB_TEXT || !STRICT_KERNEL_RWX))
+	depends on PPC_BOOK3S_32 || (PPC_8xx && !PIN_TLB_DATA && !STRICT_KERNEL_RWX)
 	help
 	  This option allows you to set the kernel data alignment. When
 	  RAM is mapped by blocks, the alignment needs to fit the size and
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 66ee62f30d36..775b4f4d011e 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -42,15 +42,6 @@
 #endif
 .endm
 
-/*
- * We need an ITLB miss handler for kernel addresses if:
- * - Either we have modules
- * - Or we have not pinned the first 8M
- */
-#if defined(CONFIG_MODULES) || !defined(CONFIG_PIN_TLB_TEXT)
-#define ITLB_MISS_KERNEL	1
-#endif
-
 /*
  * Value for the bits that have fixed value in RPN entries.
  * Also used for tagging DAR for DTLBerror.
@@ -209,12 +200,12 @@ InstructionTLBMiss:
 	mfspr	r10, SPRN_SRR0	/* Get effective address of fault */
 	INVALIDATE_ADJACENT_PAGES_CPU15(r10)
 	mtspr	SPRN_MD_EPN, r10
-#ifdef ITLB_MISS_KERNEL
+#ifdef CONFIG_MODULES
 	mfcr	r11
 	compare_to_kernel_boundary r10, r10
 #endif
 	mfspr	r10, SPRN_M_TWB	/* Get level 1 table */
-#ifdef ITLB_MISS_KERNEL
+#ifdef CONFIG_MODULES
 	blt+	3f
 	rlwinm	r10, r10, 0, 20, 31
 	oris	r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha
@@ -618,10 +609,6 @@ start_here:
 	lis	r0, (MD_TWAM | MD_RSV4I)@h
 	mtspr	SPRN_MD_CTR, r0
 #endif
-#ifndef CONFIG_PIN_TLB_TEXT
-	li	r0, 0
-	mtspr	SPRN_MI_CTR, r0
-#endif
 #if !defined(CONFIG_PIN_TLB_DATA) && !defined(CONFIG_PIN_TLB_IMMR)
 	lis	r0, MD_TWAM@h
 	mtspr	SPRN_MD_CTR, r0
@@ -739,7 +726,6 @@ _GLOBAL(mmu_pin_tlb)
 	mtspr	SPRN_MD_CTR, r6
 	tlbia
 
-#ifdef CONFIG_PIN_TLB_TEXT
 	LOAD_REG_IMMEDIATE(r5, 28 << 8)
 	LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
 	LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED)
@@ -760,7 +746,7 @@ _GLOBAL(mmu_pin_tlb)
 	bdnzt	lt, 2b
 	lis	r0, MI_RSV4I@h
 	mtspr	SPRN_MI_CTR, r0
-#endif
+
 	LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM)
 #ifdef CONFIG_PIN_TLB_DATA
 	LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET)
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index 231ca95f9ffb..19a3eec1d8c5 100644
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -186,8 +186,7 @@ void mmu_mark_initmem_nx(void)
 	mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, false);
 	mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);
 
-	if (IS_ENABLED(CONFIG_PIN_TLB_TEXT))
-		mmu_pin_tlb(block_mapped_ram, false);
+	mmu_pin_tlb(block_mapped_ram, false);
 }
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
diff --git a/arch/powerpc/platforms/8xx/Kconfig b/arch/powerpc/platforms/8xx/Kconfig
index cdda034733ff..1a8400bfbe82 100644
--- a/arch/powerpc/platforms/8xx/Kconfig
+++ b/arch/powerpc/platforms/8xx/Kconfig
@@ -202,13 +202,6 @@ config PIN_TLB_IMMR
 	  CONFIG_PIN_TLB_DATA is also selected, it will reduce
 	  CONFIG_PIN_TLB_DATA to 24 Mbytes.
 
-config PIN_TLB_TEXT
-	bool "Pinned TLB for TEXT"
-	depends on PIN_TLB
-	default y
-	help
-	  This pins kernel text with 8M pages.
-
 endmenu
 
 endmenu
-- 
2.25.0